HR: 0830h
AN: SH11D-1146    [PDF]
TI: Enrichment of suprathermal $^3$He$^{++}$ associated with interplanetary coronal mass ejection events
AU: Bamert, K
EM: karin.bamert@soho.unibe.ch
AF: Physikalisches Institut, University of Bern, Sidlerstrasse 5, Bern, 3012 Switzerland
AU: * Kallenbach, R
EM: reinald.kallenbach@issi.unibe.ch
AF: International Space Science Institute, Hallerstrasse 6, Bern, 3012 Switzerland
AU: Hilchnbach, M
EM: hilchenbach@linmpi.mpg.de
AF: Max-Planck-Institut f\"ur Aeronomie, Max-Planck-Strasse 2, Katlenburg-Lindau, 37191 Germany
AU: Wimmer-Schweingruber, R F
EM: wimmer@physik.uni-kiel.de
AF: Institut f\"{u}r Experimentelle und Angewandte Physik, University of Kiel, Leibnizstrasse 19, Kiel, 24098 Germany
AU: Klecker, B
EM: bek@mpe.mpg.de
AF: Max-Planck-Institut f\"ur Extraterrestrische Physik, Giessenbachstrasse, Garching, 85748 Germany
AB: Three types of suprathermal helium are identified by the CELIAS/(H)STOF mass spectrometer onboard SOHO: 1) solar wind $^4$He$^{++}$, 2) $^4$He$^+$ pick-up ions, and 3) $^3$He from impulsive flares (Bamert et al, 2003, Kallenbach et al., 2003). In this work we analyze the spectra of the He isotopes, and their ratio in the energy range 0.035--2 MeV/amu associated with coronal mass ejection events. We study the fractionation during propagation in interplanetary space, and during injection and acceleration at coronal mass ejection driven shocks. The $^3$He/$^4$He ratio strongly depends on the energy per mass. It varies from 0.01 at 50 keV/amu to almost 1 above 600 keV/amu. The $^3$He spectrum matches a model on stochastic acceleration in electron firehose waves in the source plasma of impulsive flares (Paesold et al., 2002) and subsequent transport through interplanetary space.
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2118 Energetic particles, solar
DE: 2139 Interplanetary shocks
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting